Screen blanks when network cable pulled

[my question is]

I'm trying to set up a wifi extender. PC has only one enet port. Can't get extender to pair with router via wifi so I connected to the extender with an enet cable. When the cable is disconnected from the router and connected to the extender the screen goes blank and stays that way until the router is reconnected.

I'm hoping this just a setting/switch somewhere. Thanks!

 

[my question is]

Attention getting bump.